Mobile was silently dropping two event types the gateway emits. This adds
parsing + UI surfacing for both, bringing mobile to parity with desktop
(which shows gateway errors as red toasts).
- `error` (backend crash) -> WsEvent.GatewayError, surfaced in the existing
error banner (mirrors how RpcError is handled).
- `background.complete` (scheduled job finished) -> WsEvent.BackgroundComplete,
surfaced as a non-blocking snackbar in ChatScreen.
Changes:
- WsEvent.kt: add GatewayError(message?) + BackgroundComplete(data?) sealed subtypes.
- EventParser.kt: handle "error" + "background.complete"; unknowns still fall
through to Unknown (no behavior change for existing event types).
- ChatWsEventReducer.kt: onGatewayError (sets errorMessage, clears loading) +
onBackgroundComplete (sets backgroundCompleteMessage); mirrors onRpcError.
- ChatViewModel.kt: backgroundCompleteMessage state field, clearBackgroundComplete(),
handleWsEvent branches (ViewModel owns the snackbar trigger).
- ChatScreen.kt: pass backgroundCompleteMessage to ChatLifecycleEffects + a
LaunchedEffect that shows the snackbar and calls clearBackgroundComplete().
- EventParserTest.kt: cover both new events (incl. missing-message case).
Pure additive; sealed class + exhaustive when() preserved. Verified:
compileDebugKotlin + ktlintCheck green; EventParserTest passes.
Closes#527
Co-authored-by: M57 <m57@hermes-control.app>
